The present invention relates generally to motion picture projectors, and more particularly, to high definition digital image projection systems for projecting high resolution images.
In the past, motion picture image projectors have typically been film projectors. Digital images also require a means for projection. Previous digital image projection solutions provide few pixels or low intensity projection such as are provided by TV screens.
The introduction of high resolution digital images with pixel sizes as large as 4000xc3x973000 pixels requires new techniques for projection. Conventional techniques that are used in many applications include large screen TV tubes used in conference rooms for applications such as PICTURETEL video conferencing. Other techniques are used for the large screen displays used at sports complexes.
Another technique is used in a Texas Instrument array of movable mirrors. This array is a set of micro-mirrors that can be rotated. When a mirror is in one orientation, the light is reflected toward a lens system used for projection. When the mirror is in another orientation, the light is reflected away from the lens system. An array of such mirrors is used to build an image. The amount of time that the mirror is oriented toward the lens system establishes the amount of light of a particular color that is projected. These arrays are generally limited in size, since it is difficult to build large arrays of such mirrors.
It would therefore be desirable to have high definition digital image projection systems that improve over conventional systems. It is therefore an objective of the present invention to provide for high definition digital image projection systems for projecting high resolution images.
To accomplish the above and other objectives, the present invention comprises a digital projection system that uses modulated lasers and is capable of projecting high resolution images at frame rates that are used in the movie industry. Brightness and dynamic range are two of the requirements for the projection system that are most difficult and that are solved by the present invention.
The present projection system uses arrays of high intensity lasers to provide high intensity images for large screen projection of high resolution images. The present projection system provides higher intensity for large screen projection of high resolution images.
An exemplary high definition digital image projection system comprises an image memory having a plurality of outputs that are controllably and precisely delayed. A plurality of digital-to-analog converters are coupled to the image memory for converting digital signals output thereby that correspond to predetermined colors that make up an image into analog signals for the respective color. A plurality of lasers have their light intensity outputs modulated by the outputs of the respective digital-to-analog converters. A plurality of optical devices such as color sensitive half-silvered mirrors or sets of prisms having color-sensitive coatings on their respective faces, are used to produce a coaxial set of laser beams. First and second rotating mirrors are used to reflect the coaxial set of laser beams and generate an image for viewing. A mirror rotation synchronization circuit synchronizes rotation of the first and second rotating mirrors.